This invention relates to an assembly which attaches a steering wheel, and electrical switches and connections on and adjacent the steering wheel, to the steering column as a modular unit.
In the prior art, the assembly of the steering wheel is typically a multi-step process. Initially, the electrical connections between the steering column and a clock spring are made. A clock spring is a known electrical connector which allows relative rotation between electrical components on the steering wheel (such as the air bag, horn, cruise control, etc.) and the electric connections leading to systems or controls on the vehicle. A clock spring typically allows several rotations of the steering wheel in either direction while maintaining electrical communications between the steering wheel mounted elements and the fixed steering column.
In the prior art, the clock spring is typically attached to structure on the steering wheel to complete the electrical connections. Moreover, switches mounted on the steering column, such as stalk switches, must also be attached prior to attachment of the steering wheel. Typically, the switches are mounted in a separate housing that must be mounted on the steering column. Once the housings are mounted, the steering wheel is attached to the wheel column. The air bag is then attached to the steering wheel. A cover for the air bag is then placed over the air bag. Typically, an ignition switch is cast into the steering column. The first time an operator may fully test all electrical connections and switches associated with the steering wheel is only after the components have been assembled onto the vehicle. If a problem is discovered, the assembler must then remove the assembly from the vehicle for repair.
The above-described assembly is relatively time-consuming, and labor intensive. Moreover, it requires the final vehicle assembly location to perform a high number of assembly steps. Further, it limits the order in which assembly steps can be performed, and requires the automobile assembly location to maintain an inventory of several different parts. In addition, all of the separate parts and housings increase the overall size of the assembly.
It is a goal of the automotive industry to reduce the number of parts that must be assembled as separate pieces, the required size for the components, and the labor required for assembly. Moreover, it is a goal of any assembly application to reduce restrictions on the order of assembly steps. Finally, it is a goal of the automotive industry to remove as much assembly function from the final vehicle assembly line as possible.